This invention relates to a method and device for surface treatment and more particularly to a method and apparatus for surface treating cylinder blocks of reciprocating machines having angularly disposed cylinder banks.
There have been proposed very effective methods and apparatus for surface treating the cylinder bores of a cylinder block. The cylinder bores may be surface treated for a variety of purposes, the main of which is to plate a hardened coating on the base cylinder block material. By plating cylinder blocks in this method, it is possible to use light alloy-based blocks and still have the desired cylinder wall surface and surface properties.
Such a plating technique has been found useful in permitting lighter weight cylinder blocks than possible when utilizing pressed or cast-in cylinder liners, as was the previous practice. Although plating has been an alternative to the use of pressed or cast-in liners, conventional plating processes are not particularly adapted for use with cylinder blocks. There are a number of reasons for this.
The first of these reasons has to do with the fact that in conventional plating processes, the entire article to be plated is submersed in the electrolytic solution. Thus, if it is desired only to plate the cylinder bores, then some form of stopping off for the other surfaces of the cylinder block must be employed.
In addition to this disadvantage, conventional dip-type plating has a number of other generally objectionable characteristics. That is, the plating baths are quite environmentally unfriendly, and the handling of the plating fluids, subsequent washing, cooling, and drying presents significant problems.
Therefore, there has been proposed a plating method wherein the surface to be plated is hydraulically sealed and a plating electrolyte fluid is passed through the area across the surface to be plated. An electrical potential is generated, and the plating of the desired surface can be accomplished quickly and in a generally environmentally safe manner.
When plating cylinder bores, it is possible, for example, to place the cylinder block with one end of the cylinder bore in sealing relationship with a supporting base. A hollow electrode is then passed through the cylinder bore, and the other end of the cylinder bore is sealed. The plating fluid is then passed through the narrow area between the outer surface of the electrode and the inner surface of the cylinder bore at a high velocity.
With this type of system, a very good plating layer can be accomplished in a very quick time and in a generally environmentally safe manner. In addition, the washing and other environmental protection required with dip-type plating are significantly improved. In fact, this type of plating method and apparatus can be utilized on a production line where other machining and finishing operations are performed on the cylinder block.
However, the type of method and apparatus previously utilized for this purpose has generally been limited to arrangements wherein the cylinder block has in-line cylinders. If in-line cylinders are employed, several cylinders may be plated at the same time. In addition, the other surface treatments required for the plating process can also be performed in a similar manner.
However, the previously proposed methods and apparatus have not lent themselves to practice with engines having their cylinder bores aligned in an angular relationship to each other. Said another and more simple way, these previously proposed methods and apparatus have not lent themselves to utilization with V-type cylinder blocks.
It is, therefore, a principal object of this invention to provide an improved method and apparatus for surface treating the cylinder bores of engines having angularly disposed cylinder banks and cylinder bores.
It is a further object of this invention to provide an improved method and apparatus for plating cylinder blocks having angularly disposed cylinder bores wherein the plating process can be accomplished with conventional type equipment utilized for in line cylinders.
As should be apparent from the foregoing description, the presently proposed plating and surface treatment apparatus and methods for cylinder blocks has been generally limited to the use of application to in line cylinder blocks. This is generally because of the fact that a seal must be established at each end of each cylinder bore. Where the cylinder bores are angularly disposed, then a problem arises in conjunction with the simultaneous sealing of a plurality of nonaligned cylinder bores.
It is, therefore, a still further object of this invention to provide an improved method and apparatus for surface treating the cylinder bores of cylinder blocks having angularly disposed relationship.
In accordance with a feature of the invention, as will be described later under the heading entitled "Summary of the Invention", the plating or surface treatment of cylinder blocks having angularly disposed cylinder bores is facilitated by first surface treating all cylinder bores that are aligned in one plane and then surface treating those cylinder bores that are aligned in another plane. Obviously, this requires manipulation of the cylinder block, and also may significantly increase the space required for the surface-treating mechanism.
It is, therefore, a still further object of this invention to provide an improved plating apparatus and method wherein cylinder blocks having angularly disposed cylinder bores may be surface treated and wherein the apparatus and method is such that the actual space required on an assembly or production line is minimized.